KR101875928B1 - Sound-absorbing fibrous Assemblies having excellent compressive recovered force - Google Patents

Abstract

The present invention relates to a web or sheet comprising 25 to 40% by weight of polyolefin hollow heterotortic fibers, 40 to 55% by weight of three strands of less than 1.5 denier and 20 to 35% by weight of low melting point short fibers, Or a sheet is fixed by heat fusion by heat bonding, and has a thickness of 10 to 35 mm, and a surface density of 150 to 600 gsm. The sound absorbing fiber assembly or spunbond nonwoven fabric excellent in compression restoring force, Fibrous aggregates.

Description

[0002] Sound-absorbing fibrous assemblies having excellent compressive restoring force are excellent compressive recovered force

The present invention relates to a sound absorbing fibrous aggregate having excellent compressive restoring force, and relates to a sound absorbing fibrous aggregate having excellent compressive restoring force, which is produced by mixing fibers having various cross sections and shapes.

Various types of sound absorbers are used in a number of different fields to absorb sound. Known sound-absorbing materials include open-cell materials such as glass wool, rock wool, sponge, felt or urethane foam; Porous materials such as porous sintered boards, metallic fiber boards or foam metal boards; An open cell chalk board; A combination of sheet material and nonwoven sound absorbing material; Or certain films.

Among various fields, a sound absorbing material for controlling the noise generated from the engine of an automobile is also widely used. In order to suppress the engine transmission noise, an engine cover or a hood insulator is generally used. However, There are some limitations to the removal.

Accordingly, a sound absorbing material is mounted on the front, the left side, and the floor of the vehicle. For example, a sound absorbing material is installed on a dash panel that separates the engine room from the vehicle room to block noise generated in the engine room. A sound absorbing material is attached to the side panel.

Generally, a sound absorbing material for an engine cover uses a nonwoven fabric produced by a meltblown method to cut off the engine output sound, tire friction sound, wind sound, etc. The microfiber sound absorbing material is a porous material composed of microfine fibers and an air layer As a material, if a sound wave enters into the sound absorbing material, the sound energy is converted into thermal energy due to friction with the fine fiber, thereby reducing noise. In addition, it has the function of a sound absorbing material having a low weight and high sound absorption performance as compared with other sound absorbing materials such as urethane foam and felt.

 Polypropylene is widely used as a sound absorbing material due to its low hygroscopicity, water releasing property and low thermal conductivity. However, it has a melting point lower than that of other polymer resins having a melting point of 160 캜 and may be relatively vulnerable to heat. Typically, polyethylene terephthalate, that is, polyester, has a melting point higher than that of polypropylene at 260 ° C, which is higher than polypropylene by 100 ° C or more. When the melting point of a polymer used as a sound absorbing material is low, the material melts in a surrounding environment where heat is generated during operation like an engine, so that it is not able to recover after being compressed under pressure, resulting in increased strain, low elasticity, and poor durability .

Korean Patent No. 10-1071193 discloses a sound-absorbing nonwoven fabric for absorbing and blocking noise, wherein a spunbond nonwoven fabric layer of long fiber spunbond is laminated on both sides of a meltblown nonwoven fabric layer to improve baldness and sound absorption, There is a disadvantage that the additional process of filming the surface is troublesome and the noise in the entire frequency band can not be blocked.

Therefore, it is necessary to develop materials and processes having high thermal stability, low compressive strain, excellent elasticity, and sound absorption properties in the entire frequency band.

An object of the present invention is to provide a fibrous aggregate having a dead air layer and having a volume stability and having a low compressive strain under pressure and excellent resilience.

The present invention also provides a fiber aggregate which is less affected by the temperature of the external environment by using a material having thermal stability.

Further, the present invention aims to provide a fiber aggregate having excellent sound absorption properties in a wide frequency band region and excellent compression restoring force.

In order to achieve the above object, the present invention provides a web comprising 25 to 40% by weight of polyolefin hollow heterotortic fibers, 40 to 55% by weight of three fineness staple fibers of less than 1.5 denier and 20 to 35% Wherein the web or sheet is fixed by heat bonding by heat bonding and has a thickness of 10 to 35 mm and a surface density of 150 to 600 gsm.

Further, in the present invention, the low melting point staple fiber is a Cisco-type discrete fiber, and the core portion is circular or hollow.

Further, the present invention provides a sound absorbing fibrous aggregate having excellent compressive restoring force, wherein the fibrous aggregate has a sound absorption degree of 0.70 to 1.10NRC and a permanent compression strain of 30% or less.

Further, the present invention provides a sound absorbing fibrous aggregate having excellent compressive restoring force, characterized in that the fibrous aggregate has a sound absorption degree of 0.70 to 1.10 NRC and a repeated compression strain of 25% or less.

Further, in the present invention, the multi-leaf shape has four or more leaf structures, and the hollow hollow short fibers include a hollow portion, a shape retaining portion, and a volume control portion, and the volume control portion has a shape protruding in the opposite direction of the fiber center And the end portion is formed in a round shape. The present invention provides a sound absorbing fiber aggregate excellent in compression restoring force.

In the present invention, it is preferable that the core portion of the Cisco-type low melting point staple fiber is formed of a polyester resin, and the sheath portion is formed of a copolymer polyester resin in which a diol component containing terephthalic acid and a diol component containing ethylene glycol is condensed The present invention provides a sound absorbing fiber aggregate excellent in compression resilience.

Further, the sound-absorbing fiber aggregate further includes a spunbond fiber aggregate composed of polypropylene or polyester, and the spunbond fiber aggregate has a surface density of 15 to 50 gsm.

The present invention has an effect of being strong against heat and excellent in compression restoring force by forming a fibrous aggregate by combining various elements of raw material, weight ratio, shape and fineness of constituent fibers.

Further, the present invention has the effect of securing a wide dead air layer, having elasticity and volume stability, hindering the transmission of sound energy in a wide frequency band and having excellent sound absorption properties.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a modified hollow short fiber according to a preferred embodiment of the present invention. FIG.
FIG. 2 to FIG. 7 are conceptual diagrams of cross-section of a hollow hollow fiber according to a preferred embodiment of the present invention.
8 is a cross-sectional view of a three-stranded staple fiber according to a preferred embodiment of the present invention.
9 is a cross-sectional view of a round-shaped Cisco-type low-melting-point staple fiber according to a preferred embodiment of the present invention.
10 is a cross-sectional view of a hollow CCSO type low melting point staple fiber according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

As used herein, the terms "substantially", "substantially", and the like are used herein to refer to a value in or near the numerical value when presenting manufacturing and material tolerances inherent in the meanings mentioned, Absolute numbers are used to prevent unauthorized exploitation by unauthorized intruders of the mentioned disclosure.

The present invention can be constituted by a web or a sheet composed of a hollow hollow short fiber, a three-fiber short fiber and a low melting short fiber.

The modified hollow short fibers 10 may have a multi-leaf shape including a plurality of leaf structures. Specifically, the modified hollow short fibers may include a hollow portion 100, a shape retaining portion 200, and a volume control portion 300. It is preferable that the hollow portion 100 has a hollow ratio of about 15 to 30% in the total area of the fibers. Above the above range, there may be a problem in fiber formability, and if it is less than the above range, the hollow retention property and the various functionalities of the present invention may be limited. The shape retaining part 200 refers to a fibrous shape between the hollow part 100 and the volume control part 300.

The volume control part 300 may protrude in a direction opposite to the center of the fiber, and the distal end may be round. At this time, the uppermost part of the distal end can be defined as the peak 310, and the space between the volume control parts can be defined as the valley 330. At this time, the radius of curvature of the peak can be defined as R, the radius of curvature of the valley as r, and the values of R and r that are different from each other can be determined for each volume controller (Fig. 3).

A value T1 is the largest distance from the center point M of the hollow portion 100 to the peak 310 and T2 the smallest distance from the center point M to the peak 310 is the center point M And the distance from the center point M to the valley 330 is defined as t2. On the other hand, a circle formed by connecting the tangent of the volume controller 300 having the next higher order distance from the center point M to the peak 310 on the basis of T1 is referred to as CTmax and T2 is defined as a peak from the center point M A circle formed by connecting the tangent of the volume controller 300 having a smaller distance from the center point M to the peak 310 is referred to as a CTmin and a distance from the center point M to the peak 310 on the basis of t1 is larger And a tangent line of the volume control unit 300 having a smaller distance from the center point M to the peak 310 is connected to the tangent line of the volume control unit 300 When the formed circle is Ctmin; The difference value between the center point CTmaxM of the CTmax and the center point M is denoted by CTmax-R and the difference between the center point CTminM of the CTmin and the center point M is denoted by CTmin-R and the center point CtmaxM of the Ctmax, When the difference value between the center point (CtminM) and the center point (M) of the Ctmin is defined as Ctmin-r, the fiber according to the present invention can satisfy the following conditions. 4 to 7)

When the deviation between the curvature radius R of the peak and the curvature radius r of the valley is defined as Z, the above Z may be defined by the following conditions (1) and (2).

(1) -3? Z? 4

≤ 1.8(2) 0.9?

1.8

here,

R: radius of curvature of peak

r: radius of curvature of the valley

Many tests by the present inventors through fiber cross-sectional morphology analysis showed that the volume control portion of one fiber was inserted into the valley between the volume control portions of the adjacent fibers in the outside of the above range to show a structural characteristic as if the gears were engaged, And it is analyzed that it has a bad influence on the uniformity of the fiber aggregate. The volume control part between the fibers interferes with each other within the above range, and the bulky property is maintained. Even if the volume control part is inserted into the valley of the adjacent fiber, the fiber control part can be easily detached by flow or the like, thereby improving uniformity in the fiber aggregate.

The fibers according to the preferred embodiment of the present invention may satisfy the following conditions: CTmax-R, CTmin-R, Ctmax-r, and Ctmin-r.

≥ 0.80(3)

≥ 0.80

≥ 0.30(4)

≥ 0.30

here,

T1: the distance from the center point M to the peak 310 is the largest value

T2: the distance from the center point M to the peak 310 is the smallest value

t1: the distance from the center point M to the valley 330 is the largest value

t2: the distance from the center point M to the valley 330 is the smallest value

CTmax: the distance from the center point M to the peak 310 on the basis of T1 is a circle formed by connecting the tangent of the volume controller 300 having the next higher order value,

CTmin: T2 is a circle formed by connecting the tangent of the volume control unit 300 having a smaller distance from the center point M to the peak 310,

Ctmax: A circle formed by connecting the tangent of the volume control unit 300 having the next higher order distance from the center point M to the peak 310 with reference to t1

Ctmin: a circle formed by connecting the tangent of the volume control unit 300 having a smaller distance from the center point M to the peak 310,

CTmax-R: Difference value between the center point (CTmaxM) and the center point (M) of CTmax

CTmin-R: Difference value between the center point CTminM of the CTmin and the center point M

Ctmax-r: Difference value between the center point (CtmaxM) and the center point (M) of Ctmax

Ctmin-r: Difference value between the center point (CtminM) and the center point (M) of Ctmin

The above conditions (3) and (4) may relate to the formation of fibers according to an embodiment of the present invention. Ideally, the value should be 1, but not 1 due to the rheological properties of the polymer. The condition (3) may be related to formation of the volume control portion. Outside of the above range, the deviation of the volume control portion may be large and the variation of the r value may be large, which may affect the carding property in the process or the bulkiness in the fiber aggregate. Condition (4) can be interpreted as fiber morphology, which can affect the formability of hollow portion 100 and shape retaining portion 200. Outside of the above range, hollow formation and fiber shape retention may be unstable.

In the present invention, the multi-lobe shape of the hollow short staple fibers means that four or more lobe structures are formed, and specifically, 4 to 12 volume control portions may be formed on the surface of the hollow short staple fibers. The formation rate of the dead air layer is increased by forming four or more leaves, and the gas molecules inside the dead air layer are subjected to molecular motion to form elasticity and volume stability. The volumetric stability is formed so that even if a constant pressure is formed, the molecular motion is resumed when the polymer is removed, and recovery is achieved, and compression strain is low. Further, sound energy is diffracted or diffused or converted into heat energy by the dead air layer, so that the sound absorbing property is increased and the warming property can be increased by the heat insulating effect of the dead air layer.

The weight ratio of the hollow hollow short fibers constituting the web or sheet is 25 to 40% by weight, preferably 25 to 35% by weight, more preferably 25 to 30% by weight.

If the molecular weight of the hollow short staple fibers is less than 25% by weight, the amount of the dead air layer and the hollow portions may be reduced to reduce the sound absorption effect in the wide frequency region and to slow the compression recovery by molecular motion. The density of the tissue is reduced, so that the durability can be weakened although it is lightweight. The hollow portion has a sound absorbing effect in the entire frequency band including the high frequency and the low frequency.

In the constitution of the present invention, the three-fineness staple fibers may be formed into three fineness sizes commonly used, and preferably, three fineness staple fibers of less than 1.5 denier. Since the three-fineness of less than 1.5 denier is formed by short fibers, more layers are ensured when the same thickness is laminated, thereby increasing the density of the structure. Thus, even if the thickness is thin, sound absorption and heat insulation are improved and a dense structure of the fiber aggregate is formed to enhance durability .

The weight ratio of the three strands of the short fibers constituting the web or sheet is 40 to 55% by weight, preferably 40 to 45% by weight. If it is less than 40% by weight, the durability may be weak due to the low density of the tissue. If it exceeds 55% by weight, securing of the dead air layer may be reduced, and elasticity and volume stability may be deteriorated.

Among the constitution of the present invention, the low melting point staple fibers may be used as binder fibers, i.e., binders, which are used for thermal fusion in the heat bonding process.

 The low melting point staple fibers constituting the web or sheet may be 20 to 35% by weight, and preferably 20 to 25% by weight. If it is less than 20% by weight, the bondability due to thermal fusion may decrease, and productivity may be deteriorated. If it is more than 35% by weight, the amount of the binder to be melted is large and the volume stability is broken. And the sound absorption property may be deteriorated.

The shape of the low-melting point staple fiber is not limited, but preferably is a Cisco-type mold release fiber, and the core portion may be circular, hollow or partially hollow. If the core portion is hollow, it can be used as a constituent fiber for restoring compression and sound absorption, and it can hinder sound energy in a wide frequency band due to hollow, thereby improving sound absorption. Also, the dead air layer secured in the hollow can secure the volume stability.

In one embodiment of the present invention, the low melting point staple fiber is a Cisco hollow hollow having a sheath portion and a core portion, the core portion is formed of a polyester resin, and the sheath portion includes a dicarboxylic acid component containing terephthalic acid and ethylene glycol The diol component may be formed of a co-polymerized copolymer polyester resin.

The polyester resin of the core part may use any one of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT).

If the intrinsic viscosity of the polyester resin is high, the hollow shape in the core portion in the core portion may be increased in the direction of the inner circumference during the production of the hollow cis-core type thermally adhesive composite fiber, and the hollow ratio may be decreased. The viscosity is preferably 0.50 to 0.64 dL / g.

The copolymerized polyester of the sheath portion formed as described above is characterized in that it shows only the softening behavior without melting point.

The hollow hollow low-melting-point short fiber according to one embodiment is a hollow-type conjugate fiber, and the hollow ratio is a factor that directly affects the multifunctional performance such as lightness, bulging, sound-absorbing property and warmth. If the hollow ratio is too low It is preferable that the hollow ratio is 7% or more since the multifunctional performance such as lightweight, bulky, sound-absorbing, warming, and volume stability may be deteriorated.

The sheath portion and the core portion may be formed to have a weight ratio of 30:70 to 70:30 to form the Cisco hollow hollow low melting point short fiber of the present invention.

The staple fibers of the present invention can be made of any material that can be formed into a fibrous form. Preferably, polyester may be used, but not limited thereto, polyethylene, polypropylene (PP), nylon and the like can be used.

The polyester resin may be at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalic acid (PTT), polyethylene naphthalate (PEN), polyethylene terephthalate glycol (PETG), polycyclohexane Dimethylene terephthalate (PCT). ≪ / RTI >

However, in the present invention, the fiber aggregate is formed by fixing by heat fusion by the heat bonding process. It is preferable to prevent the fiber aggregate from being damaged by using a raw material or material having excellent thermal stability. For example, polypropylene has a melting point of 160 ° C, whereas polyester has a melting point of 260 ° C. Therefore, it is preferable to fix a fiber aggregate by a heat bonding process to maintain multifunctional properties such as recoverability, sound absorption, have.

The fibrous aggregate according to an embodiment of the present invention can be made of polyester which is a thermoplastic resin as a non-limiting example, and it can be produced in a short fiber state or a fibrous aggregate form through spontaneous crimp expression due to a difference in crystallization rate in cooling and solidification processes. It can contribute to improving the balance and elasticity.

Although the thickness of the fibrous aggregate is not limited, it is preferably 10 to 35 mm, more preferably 15 to 25 mm in order to improve sound absorption and compression recovery. If it is less than 10 mm, the functionality such as sound absorption properties and compression restoring force deteriorates. If it exceeds 35 mm, there is an additional process or inconvenience in subsequent processing and use.

Although the area density of the fibrous aggregate is not limited, it is preferably from 150 to 600 gsm, more preferably from 250 to 500 gsm, in order to improve sound absorption and compression recovery.

When the surface density is less than 150 gsm, there is a problem that the thermal stability is decreased and the sound absorption property is lowered. When the surface density is more than 600 gsm, the lightweight property is deteriorated and the elasticity and compression resilience are deteriorated.

The fibrous aggregate not only has a sound-absorbing property but also has a compressive strain lower than that of the fiber aggregate and has excellent resilience.

In addition, the fibrous aggregate may further include a separate spunbond fiber aggregate. The area density of the spunbond fiber aggregate is 15 to 50 gsm, preferably 25 to 35 gsm. In one embodiment, a nonwoven fabric in which a spunbond nonwoven fabric 50 gsm is bonded to 380 gsm of a nonwoven fabric formed by the heat bonding process by heating bonding can be formed.

The raw material constituting the spunbond fiber aggregate is not limited, but polypropylene or polyester is generally used in a large amount. In addition, the shape and fineness are not limited, and it includes various shapes such as circular, divergent, cisco, and hollow, and includes all three finenesses and finenesses.

When the spunbond fiber aggregate is further included, the micropores of the fibers are much contained, thereby increasing voids and improving the sound absorption as the density of the tissue increases.

The spunbond fiber aggregate is a fibrous aggregate of long fibers using filaments. According to one embodiment of the present invention, the heat-bonding fiber aggregate composed of short fibers and the spunbond fiber aggregate composed of long fibers interact with each other to increase irregular arrangement of pores and voids, thereby increasing the conversion ratio of negative energy to diffuse reflection and thermal energy Sound absorption properties can be improved.

The process for producing the sponge filament aggregate according to the present invention comprises a commonly used process. Specifically, the process may include a process of directly spinning the polymer into a continuous filament, a process of laminating and laminating the web, forming a web, and a bonding process of stabilizing the shape.

Hereinafter, this embodiment will be described. However, the present invention is not limited to the examples.

(De 'stands for denier which is fiber unit).

Example 1

(PET) hollow short staple fiber 30 wt%, polyester (PET) 0.7De ', 40 wt% of a three-kind staple short fiber, 30 wt% of circular polyester-type polyester (PET) A nonwoven fabric prepared by a heat bonding process by heat bonding is prepared. The surface density of the heat-sealed nonwoven fabric is 380 gsm and the thickness is 20 mm.

Example 2

The same fibers as in Example 1 were used, with a surface density of 430 gsm.

Example 3

The same fibers as in Example 1 were used, and further, 50 gsm of a polypropylene spunbond nonwoven fabric was further included.

Example 4

The same fibers as in Example 1 were used, and hollow CCS type low melting point short fibers were used, and further, 50 gsm of polypropylene spunbond nonwoven fabric was further included.

Comparative Example 1

Same as Example 1 except that the hollow hollow short fibers are round short fibers.

Comparative Example 2

Same as Example 1 except that the hollow hollow short fibers are round hollow short fibers.

Comparative Example 3

The same as Example 1, except that the fiber had a fineness of 1.8 De 'instead of three strands of PET having a fiber size of 0.7 De'.

Comparative Example 4

70% by weight of PET hollow hollow short fibers and 30% by weight of circular low-melting short-fiber type short fibers were mixed in the same manner as in Example 1, except for the three fineness staple fibers having a PET 0.7De '.

Comparative Example 5

Same as Example 3 except that the hollow short hollow fibers were replaced by circular short fibers.

Comparative Example 6

Same as Example 3 except that the hollow hollow short fibers were replaced with circular hollow short fibers.

Comparative Example 7

The same as Example 3, except that the fiber had a fineness of 1.8De in place of the fineness staple fiber of 0.7De '.

Comparative Example 8

70% by weight of the PET hollow hollow short fibers and 30% by weight of the round type low-melting point short-fiber type fiber were mixed except for the three fine stranded fibers having the same structure as that of Example 3 except for the PET 0.7De '.

Comparative Example  9

Meltblown microfibers and PET circular cross-section fibers are used in a weight ratio of 50:50 to produce a meltblown fiber web. The weight is 430 gsm and the thickness is 20 mm.

Comparative Example  10

The same as in Comparative Example 9, except that the hollow cross-section monofilament was used instead of the circular cross-section monofilament.

Comparative Example  11

The same as in Comparative Example 9, except that the hollow circular cross-section monofilament was used instead of the circular cross-section monofilament.

end. Permanent compressive strain

 Using the equipment according to KS M 6518, the produced nonwoven fabric was compressed to 75% of the initial nonwoven fabric thickness for 22 hours and the permanent compression strain was measured by the following equation as the thickness after 1 hour after the compression removal.

* Permanent compression strain (%) = (initial nonwoven fabric thickness compressed nonwoven fabric thickness) / (initial nonwoven fabric thickness) * 100

      I. Repeated compressive strain

The nonwoven fabric was repeatedly compressed 120 times for 30 minutes at a pressure of 85 kgf by the self-evaluation method, and repeated compression deformation was measured by the following equation at a thickness after one hour.

Repeated compressive strain (%) = (initial nonwoven fabric thickness compressed nonwoven fabric thickness) / (initial nonwoven fabric thickness) * 100

All. Sound absorption measurement by reverberation method

It was measured using equipment conforming to ISO 354 (KS F 2805: Sound absorption level measurement method of reverberation room). The size of the specimen is 1.0m x 1.2m, and the reverberation time is 20dB when compared with the initial eeppressure. The sound source is a 1/3 Octave band sound source. Sound absorption was measured in the frequency range from 0.4 to 10 kHz.

*

a: reverberation method

c: Sound velocity in air (m / s)

c = 331 + 0.6t (t: air temperature)

S: Sample area (㎡)

V: Reverberation room capacity (㎥)

T2: Reverberation time without sample (s)

T1: reverberation time (s)

division Sound Absorption (NRC) frequency
(Hz) Example 1 Example 2 Example 3 Example 4 0.4k 0.22 0.25 0.39 0.40 0.5k 0.37 0.40 0.55 0.56 0.63k 0.48 0.51 0.58 0.60 0.8k 0.60 0.63 0.68 0.75 1k 0.60 0.62 0.85 0.89 1.25k 0.70 0.75 0.92 0.95 1.6k 0.78 0.80 0.98 1.02 2k 0.76 0.82 1.05 1.07 2.5k 0.77 0.85 1.04 1.10 3.15k 0.75 0.85 0.98 1.00 4k 0.76 0.84 0.95 0.99 5k 0.77 0.83 0.94 0.98 6.3k 0.70 0.80 0.88 0.90 8k 0.73 0.79 0.86 0.89 10k 0.72 0.79 0.92 0.92 Permanent compression
Strain (%) 29 29 30 28 Repeated compression
Strain (%) 24 23 24 22

As compared with Example 1 and Example 2, as the thickness becomes thicker, the pores become larger and the sound-absorbing property becomes better. Comparing Example 2 and Example 3, when the spunbond nonwoven fabric is included at the same area density, can confirm.

Comparing Example 3 and Example 4, it can be confirmed that excellent sound absorption and compression restoring force are obtained when using a Cisco-type low melting point staple fiber.

division Sound Absorption (NRC) frequency
(Hz) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 0.4k 0.16 0.18 0.20 0.18 0.5k 0.24 0.25 0.31 0.30 0.63k 0.30 0.33 0.35 0.33 0.8k 0.35 0.38 0.42 0.37 1k 0.35 0.40 0.45 0.39 1.25k 0.49 0.52 0.55 0.53 1.6k 0.52 0.60 0.62 0.53 2k 0.55 0.60 0.63 0.55 2.5k 0.57 0.61 0.64 0.58 3.15k 0.60 0.64 0.67 0.62 4k 0.61 0.65 0.68 0.63 5k 0.64 0.69 0.71 0.65 6.3k 0.60 0.62 0.65 0.63 8k 0.59 0.60 0.62 0.61 10k 0.68 0.71 0.73 0.72 Permanent compression
Strain (%) 43 40 35 37 Repeated compression
Strain (%) 34 31 28 30

Comparing Example 1 with Comparative Examples 1 and 2, it was found that using a hollow hollow short staple fiber is superior to a staple fiber having no hollow or other shape and having better sound absorption and compression recovery ability, and comparing Example 1 with Comparative Examples 3 and 4, It can be confirmed that when the fiber including three fineness less than denier is included, the absorbability and compression recovery ability are excellent.

division Sound Absorption (NRC) frequency
(Hz) Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 0.4k 0.18 0.20 0.22 0.20 0.5k 0.37 0.38 0.44 0.42 0.63k 0.41 0.45 0.47 0.45 0.8k 0.47 0.50 0.55 0.49 1k 0.48 0.56 0.57 0.53 1.25k 0.62 0.67 0.69 0.67 1.6k 0.65 0.73 0.74 0.66 2k 0.67 0.72 0.76 0.67 2.5k 0.68 0.73 0.78 0.75 3.15k 0.69 0.74 0.79 0.78 4k 0.70 0.71 0.79 0.78 5k 0.72 0.79 0.80 0.79 6.3k 0.73 0.75 0.78 0.75 8k 0.70 0.72 0.77 0.74 10k 0.71 0.71 0.72 0.70 Permanent compression
Strain (%) 41 39 35 36 Repeated compression
Strain (%) 33 30 28 30

Comparing Example 3 with Comparative Examples 5 and 6, even when a spunbond nonwoven fabric was mixed, it was found that using a hollow hollow short fiber was superior to a short fiber having no hollow or circular or different shape, And Comparative Examples 7 and 8, it can be confirmed that the fiber having excellent fineness and compression resilience is excellent when it contains three filaments of less than a certain denier.

That is, when a hollow short staple fiber, a three-staple short staple fiber having a certain fineness or less and a short hollow staple fiber having a short hollow fiber structure are formed, a considerable amount of dead air layer is secured to form a volume stability, The related functions can be excellent. Further, when the spunbond nonwoven fabric is bonded, a more excellent effect can be confirmed.

division Sound Absorption (NRC) frequency
(Hz) Comparative Example 9 Comparative Example 10 Comparative Example 11 0.4k 0.15 0.18 0.20 0.5k 0.22 0.25 0.29 0.63k 0.31 0.32 0.35 0.8k 0.35 0.37 0.41 1k 0.40 0.38 0.43 1.25k 0.48 0.51 0.55 1.6k 0.55 0.57 0.60 2k 0.60 0.57 0.60 2.5k 0.62 0.58 0.60 3.15k 0.63 0.62 0.68 4k 0.65 0.64 0.65 5k 0.64 0.65 0.67 6.3k 0.60 0.59 0.61 8k 0.61 0.58 0.62 10k 0.65 0.70 0.72 Permanent compression
Strain (%) 84 78 65 Repeated compression
Strain (%) 78 70 53

Comparative Examples 9 to 11 relate to nonwoven fabrics produced by a meltblown process. Nonwoven fabrics produced by heat-sealing using a low melting point staple fiber by a heating process have excellent sound-absorbing properties and have a low compressive strain and excellent resilience can confirm.

If the permanent compression strain is low, it has a low compressive strain even under prolonged pressurization and has excellent resilience. Further, when the repeated compression strain is low, excellent recovery force can be obtained even when repetitive pressure is applied as compared with the fibrous aggregates having different structures, and the elasticity is excellent.

This is because the air molecules existing in the dead air layer of the present invention undergo the intrinsic molecular motion after the pressure is removed, and the compression is restored by the force pushing each other, so that the strain is formed to be low.

Generally, the melt blown nonwoven fabric is generally made of polypropylene (PP), and the melting point thereof is relatively low due to the polyester (PET), so that the thermal stability is low. However, the polyester The nonwoven fabric of the heat fusion process has a relatively high melting point, and thus has excellent thermal stability and can be easily applied in an environment having a high ambient temperature. One embodiment of the present invention is concerned with not only the selectivity to resins suitable as raw materials, but also the structure and shape properties of short fibers.

Claims (7)

A web or a sheet composed of 25 to 40% by weight of polyolefin hollow hollow short fibers, 40 to 55% by weight of three-fineness staple fibers of less than 1.5 denier and 20 to 35% by weight of low melting short staple fibers,
Wherein the staple fiber is formed of a Cisco-type conjugate fiber, the core portion is formed of a polyester resin, the sheath portion is formed of a copolymer polyester resin in which a diol component including terephthalic acid and a diol component including ethylene glycol is condensation-
The polyester resin of the core portion has an intrinsic viscosity of 0.50 to 0.64 dL / g, a hollow ratio of 7%
The web or sheet is fixed by heat fusion by heating bonding,
A thickness of 10 to 35 mm, and a surface density of 150 to 600 gsm. The method according to claim 1,
Wherein the low-melting-point staple fiber is a Cisco-type discrete fiber, and the core portion is circular or hollow. The method according to claim 1,
Wherein the fibrous aggregate has a sound absorption degree of 0.70 to 1.10 NRC and a permanent compression strain of 30% or less. The method according to claim 1,
Wherein the fiber aggregate has a sound absorption degree of 0.70 to 1.10 NRC and a repeated compression strain of 25% or less. The method according to claim 1,
The multi-leaf shape has four or more leaf structures,
Wherein the modified hollow short fibers comprise a hollow portion, a shape retaining portion, and a volume control portion,
Wherein the volume control part may be in the form of protruding in a direction opposite to the fiber center, and the end part is formed in a round shape. delete 6. The method according to any one of claims 1 to 5,
Wherein the sound absorbing fibrous assembly further comprises a spunbond fiber assembly composed of polypropylene or polyester,
Wherein the spunbond fiber aggregate has a surface density of 15 to 50 gsm.

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